1. Field of the Invention
This invention relates to rotary engines powered by compressed air or steam, specifically to a rotary engine using compressed air or steam that produces power more advantageously than a combustion engine. The most preferred embodiment of the present invention rotary engine has a two-part casing that houses a rotor having three equally spaced-apart vanes/pistons (hereinafter referred to as pistons without intent of limitation) secured to the rotor via slots. During use of the present invention, the rotor and its three vanes are its only moving parts. Also, the casing fits closely around the rotor and pistons, which are centered within the casing. In addition, the free ends of the pistons are angled to form a tip, and each piston further contains an internally positioned spring that biases the angled piston tip against the interior surface of the casing to create a reactionary force upon start up. The pistons divide the interior space within the casing into three working chambers, and each revolution of the rotor within the casing produces three power strokes. The pistons are hollow and receive high pressure steam or compressed air from a center fixed valve having two inlet ports in opposed positions from one another. Thus, as the pistons rotate within the casing, injection of high pressure steam or compressed air into each piston occurs twice during one revolution of the rotor. Each piston also contains an opening adjacent to its angled free end through which the high pressure steam or compressed air used to produce power is delivered into the working chamber behind it. The delivery/end openings in all pistons are identically oriented away from the direction of rotor rotation.
The interior surface of the present invention casing has two arcuate lobes separated by two opposed flattened areas across which the pistons also move during their rotation. Furthermore, two exhaust ports are formed through the casing in opposed positions, each adjacent to a different one of the flattened areas and in a location that allows each piston to move across it prior to reaching the adjacent flattened area. Shortly after a piston passes one of the flattened areas and before the piston ahead of its has moved across the next approaching exhaust port to open it, the piston passing the flattened area will advance into a position where it is in fluid communication with the center valve through inlet ports, wherein it will begin to receive high pressure steam or compressed air from the center valve and release it into the working chamber behind it. However, as the piston continues to rotate, pressure continues to build in the working chamber in front of it, as the piston ahead of it will not yet have uncovered the exhaust port associated with the second flattened area (that is in an opposed location from the first flattened area). Once the exhaust port becomes uncovered, the advancing piston begins to move the steam or air from the previous power cycle through the exhaust port, giving a power boost to the piston ahead of it. Shortly thereafter, the piston ahead of it will come into fluid communication with the center valve via the opposing inlet port, and begin to release high pressure steam or compressed air into the working chamber ahead of it causing pressure to build in that working chamber until the piston ahead of it uncovers the next approaching exhaust port. When the present invention is used to power a motor vehicle, it will stop when the vehicle it powers is at rest, such as during a temporary stop at a traffic light. In addition, the present invention rotary engine has many advantages over a combustion engine, including but not limited to, the present invention is inexpensive to manufacture as there is not much tooling needed to make it; increasing horsepower simply involves increasing the width dimensions of the casing, rotor, and pistons; no crankshaft or connecting rods are needed when it is used to power a vehicle; it runs silently; compressed air adds no fuel weight/load to the vehicles it powers; it uses a small volume of air per cycle because the air is able to travel through its pistons; no wasteful energy is needed to cool it; no flammable fuel is used; it has breathable exhaust; no starter is required; and it instantly starts in cold weather. Also, air compressors associated with the present invention rotary engine can be electrically and/or mechanically driven. Applications are varied and many, including providing more reliable and economical power for motorized vehicles than is possible with a combustion engine. A small and compact present invention rotary engine has sufficient power to run a four passenger vehicle at 80-mph, with added horsepower easily achieved for larger vehicles by widening working chambers, piston, and rotor.
2. Description of the Related Art
Prior art rotary engines are known to comprise triangular-shaped rotors and vaned rotors, and many have their rotors mounted on eccentric shafts. Also, the rotor housings used in prior art rotary engines are known to comprise circular interior surfaces and two-lobed epitrochoidal interior surfaces. The rotary mechanism disclosed in U.S. Pat. No. 3,891,357 to Davis (1975) includes an interior surface having two arcuate lobes separated by two opposed flattened areas, as is found in the present invention. However, it also has differing structure to include an eccentric shaft/rotor relation, cooling nozzles 92 in ends walls 22 and 24 that provide a stream of cooling liquid to cool the rotor, exhaust ports 102 also through the end walls 22 and 24, and a gas inlet 100 through each of the opposed flattened areas. Furthermore, the Davis invention has structure configured to overcome oil sealing problems encountered with Wankel-type engines. The fixed center valve with opposing inlet ports, the peripheral exhaust ports, and the three-vane structure of the present invention are not disclosed as a part of the Davis invention. U.S. Pat. No. 4,047,856 to Hoffman (1977) discloses a rotary steam engine having a triangular-shaped hollow rotor, an eccentric shaft/rotor relation, radial grooves 72a-c and 73a-c in fluid communication with inlet ports 82 and 83 that help to conduct pressure fluid from the hollow rotor to the cavity lobes 20 and 21, and exhaust passages 80 and 81 through the housing wall. The present invention has no similar grooves and no eccentric shaft/rotor relation, and the Hoffman invention has no fixed center valve with opposing inlet ports, the peripheral exhaust ports, and the three-vane structure critical to the present invention. U.S. Pat. No. 4,115,045 to Wyman (1978) further discloses a rotary motor with spring-biased seals on the outer circular periphery of its rotor 12. Its rotor 12 has a hub 10, twenty-four radial spokes, and a circular rim 26. Multiple working chambers are defined by the seals, and a series of steam inlet and exhaust steam outlet pairs communicated with the chamber as the rotor is rotated by expansion of live steam against the radial spokes 24. Although both have vaned rotors, many differences exist between the Wyman motor and that of the present invention including the number of vanes and the number and positioning of inlet ports and exhaust ports.
Although important differences exist between it and the present invention, the rotary motor thought to be the closest to the present invention is the rotary motor disclosed in U.S. Pat. No. 1,953,378 to Vias (1934). The Vias invention comprises two adjacently positioned rotor housings having back-pressure eliminating ports that are able to move trapped fluid from one paired housing into the other according to need. Each housing also has one rotor with two vanes, and each vane having an expansion spring that constantly maintains it in engagement with the periphery of the housings working chamber (see page 1, lines 75-77). Thus, although the Vias motor has vanes with spring biasing similar to that used in the present invention, it does not teach the remainder of the present invention. Important differences in structure between the present invention and the Vias invention is that the present invention does not teach a paired housing structure with back-pressure eliminating ports, and the present invention rotor is centered within its casing, not eccentrically disposed therein. Also, the Vias motor has a cylindrical working chamber 17 with a circular periphery (see page 1, line 50 and FIGS. 3-4), while the present invention has an interior surface with two semi-circles separated by two opposed flattened areas, and in addition, its inlet ports and exhaust ports have different locations from that in the Vias motor. Also in the Vias invention, each rotor is formed with a centrally located circular exhaust chamber 23 (see page 1, lines 81-82). In the Vias invention, its intake ports 26/27 are formed through cylindrical members 16 and 16a (see FIGS. 2-4), its outlet ports 24/25 are formed through end head members 10 (see FIG. 2), and its exhaust chamber 23 is centrally located (see FIG. 4). In the present invention the opposite occurs, and a fixed valve having two opposed inlet ports is centrally located and two exhaust ports each located adjacent to a different one of the two opposed flattened area across which the free angled end of the pistons collectively move before they reach the adjacent flattened area. No other rotary engine is known to have the same structure, function in the same manner, or provide all of the advantages of the present invention.